JPH04356668A - Air conditioner - Google Patents

Abstract

PURPOSE:To provide an air conditioner which eliminates the trouble such as pressure loss in an electronic control expansion valve and relieves the work load on the user, even when only one of a plurality of indoor heat exchangers is replaced with the heat exchanger having a higher grade of max. heat exchanging volume than the others in a refrigerating cycle adaptable to the indoor heat exchanger having the reference max. heat exchanging volume. CONSTITUTION:Opening and closing valves 13a and 13b are provided on the refrigerant introducing side of an indoor heat exchanger B having the reference max. heat exchanging volume. The bypass circuits 14, 15 are provided leading from a point between the valve 13a, 13b and an electronic control expansion valve 8a, 8b to a point between a large indoor heat exchanger A having the max. heat exchanging volume and an electronic control expansion valve 7a, 7b. Bypass opening and closing valves 16 and 17 are provided on these bypass circuits, respectively, and when the thermal loading near the max. heat exchanging volume of the large indoor heat exchanger is required, the aforesaid opening and closing valves are closed and the bypass opening and closing valves are opened to conduct all the refrigerant into the large indoor heat exchanger.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to an air conditioner in which a plurality of indoor heat exchangers are connected in parallel and each uses an electronically controlled expansion valve as a pressure reducing device. , relates to a refrigeration cycle structure that makes it possible to combine an indoor heat exchanger with a standard maximum heat exchange capacity and an indoor heat exchanger with a larger heat exchange capacity.

0002

BACKGROUND OF THE INVENTION Recently, there has been a tendency for air conditioners called multi-room multi-air conditioners to be used frequently. this is,
A refrigeration cycle circuit as shown in FIG. 2 is constructed.

Namely, numeral 1 in the figure is a variable operating frequency compressor, and a four-way valve 2 is installed on the gas discharge side of the compressor 1.
and an outdoor heat exchanger 3 are connected in sequence, and a parallel circuit 4 is connected between the outdoor heat exchanger 3 and another port of the four-way valve 2.

In the parallel circuit 4, two indoor heat exchangers 5 and 6 are connected in parallel, and each of the indoor heat exchangers 5 and 6 is arranged in a different air-conditioned room. On both sides of each indoor heat exchanger 5, 6, there are electronically controlled expansion valves 7a, 8a as pressure reducing devices,
Electronically controlled expansion valves 7b and 8b as flow rate regulating valves are connected.

The electronically controlled expansion valves 7a and 8a control the throttling amount of the refrigeration cycle in accordance with the amount of superheat in the refrigeration cycle, and the electronically controlled expansion valves 7b and 8b control the amount of throttling in accordance with the operating frequency of the compressor 1. to control the flow rate of the refrigeration cycle.

[0006] Packed valves 9 are provided between each of the indoor heat exchangers 5 and 6 and the electronically controlled expansion valves 7a on both sides. It constitutes a connection part for piping connection between each indoor unit and an outdoor unit that accommodates other refrigeration cycle components.

Another port of the four-way valve 2 and the compressor 1
An accumulator 10 is provided between the suction sides of. The discharge side of the compressor 1 and the outdoor heat exchanger 3 are connected to a defrosting bypass circuit 12 having a defrosting on-off valve 11 in the middle thereof.
will be communicated directly.

In an air conditioner equipped with such a refrigeration cycle circuit, the four-way valve 2 is switched during cooling operation.
The refrigerant is guided in the direction of the solid line arrow in the figure. The refrigerant evaporates in each of the indoor heat exchangers 5 and 6, removes latent heat of vaporization from the air-conditioned room, and performs a cooling effect.

During heating operation, the four-way valve 2 is switched to guide the refrigerant in the direction of the dashed arrow in the figure. The refrigerant is condensed in each of the indoor heat exchangers 5 and 6, and the heat of condensation is released into the air-conditioned room, producing a heating effect.

0010

[Problems to be Solved by the Invention] In this type of conventional air conditioner, it is difficult to connect multiple indoor heat exchangers (5 and 6 in this case) to one outdoor unit. However, the maximum heat exchange capacity of the indoor heat exchangers 5 and 6 is unified to a predetermined reference value. In other words, a refrigeration cycle is configured that is compatible with the indoor heat exchangers 5 and 6 having the standard maximum heat exchange capacity.

However, the heat loads of the plurality of rooms to be air-conditioned are not necessarily all within the reference value of the maximum heat exchange capacity of the indoor heat exchangers 5 and 6. Depending on the conditions of the air-conditioned room to be installed, the heat load may sometimes require a maximum heat exchange capacity exceeding the standard value.

[0012] If the heat load conditions of all the air-conditioned rooms require more than the standard value, it is sufficient to adopt a set of air conditioners configured for the maximum heat exchange capacity of the next higher rank. , no problems.

However, among the multiple air-conditioned rooms, only one air-conditioned room lacks capacity and requires a higher rank, and the remaining air-conditioned rooms are within the maximum heat exchange capacity of the standard. There is a problem under heat load conditions that can be met.

One possible solution is to use an air conditioner with a maximum heat exchange capacity one rank higher than the indoor heat exchanger as well as the outdoor unit. That is, by setting the air conditioner set to one rank higher, a necessary and sufficient air conditioning effect can be obtained in any air conditioned room. However, in this case, since the rank is higher, the price and running cost of the entire air conditioner will increase, resulting in a heavy burden on the user.

As another solution, as shown in FIG.
Indoor heat exchanger A, which has a maximum heat exchange capacity one rank higher, is installed in air-conditioned rooms that have a larger heat load than other air-conditioned rooms, and in air-conditioned rooms that are within the heat load range of the remaining standards, A refrigeration cycle including an indoor heat exchanger B having a reference maximum heat exchange capacity is considered.

[0016] In this case, the price increase is only for the indoor heat exchanger A, so there is an advantage that the increase in burden on the user side is relatively small. However, when the refrigeration cycle is actually operated, the pressure drop at the electronically controlled expansion valve on the A line side of the indoor heat exchanger becomes large during the maximum heat load, resulting in a decrease in capacity, an absolute refrigerant amount shortage, and so on. Problems such as dew formation and high pressure increases occur, significantly reducing the reliability of the refrigeration cycle.

Therefore, as shown in FIG. 3, an indoor heat exchanger A with a maximum heat exchange capacity one rank higher is installed only in the required air-conditioned room, and the remaining air-conditioned rooms that are within the standard heat load range are It would be convenient for the user to obtain a refrigeration cycle that is equipped with an indoor heat exchanger B with the standard maximum heat exchange capacity in the room, and that can eliminate the occurrence of the above-mentioned problems. It is requested that air conditioners be provided.

The present invention has been made in view of the above circumstances, and its purpose is to provide an indoor heat exchanger with a standard maximum heat exchange capacity and an indoor heat exchanger with a larger maximum heat exchange capacity. The purpose of the present invention is to provide an air conditioner that can be used in combination with an electronically controlled expansion valve, eliminates problems such as pressure loss in the electronically controlled expansion valve, improves the reliability of the refrigeration cycle, and reduces the burden on the user.

[0019]

[Means for Solving the Problems] In order to achieve the above object, the present invention connects a plurality of indoor heat exchangers in parallel to a refrigeration cycle circuit, and connects a plurality of indoor heat exchangers to a refrigerant introduction side of each indoor heat exchanger. In an air conditioner equipped with an electronically controlled expansion valve, the indoor heat exchanger described above can be combined with an indoor heat exchanger with a standard maximum heat exchange capacity and an indoor heat exchanger with a larger heat exchange capacity. In order to The air conditioner is characterized in that the expansion valve is communicated with the expansion valve through a bypass circuit, and the bypass circuit is provided with a bypass on-off valve.

[0020]

[Operation] When the maximum heat load is required in an air-conditioned room equipped with an indoor heat exchanger with a large heat exchange capacity, the on-off valve on the refrigerant inlet side of the indoor heat exchanger with the standard maximum heat exchange capacity is closed. death,
By opening the bypass on-off valve of the bypass circuit,
In addition to reducing pressure loss in each electronically controlled expansion valve, all refrigerant is guided to an indoor heat exchanger with a large heat exchange capacity.
Provide sufficient heat exchange action.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a refrigeration cycle circuit of an air conditioner called a so-called multi-room multi-air conditioner. The compressor 1, four-way valve 2, outdoor heat exchanger 3, accumulator 10, and defrosting bypass circuit 12, except for the parallel circuit 4A to be described later, may be the same as the conventional ones explained earlier in FIG. Numbers are given and new explanations are omitted.

The parallel circuit 4A includes an indoor heat exchanger A whose maximum heat exchange capacity is one rank higher (hereinafter referred to as a large indoor heat exchanger), and a smaller one with a standard maximum heat exchange capacity. An indoor heat exchanger (hereinafter referred to as a reference indoor heat exchanger) B is arranged in each air-conditioned room according to each request.

Electronically controlled expansion valves 7a, 7a as pressure reducing devices are connected to the liquid side of these indoor heat exchangers A, B.
On the gas side, electronically controlled expansion valves 7b and 8 are used as flow rate regulating valves.
b is connected. All electronically controlled expansion valves 7a may be adapted to the maximum heat exchange capacity of the reference indoor heat exchanger B. Further, the compressor 1, the outdoor heat exchanger 3, etc. may be similarly adapted to the maximum heat exchange capacity of the reference indoor heat exchanger B.

[0025] Packed valves 9, 9 similar to the conventional ones are provided between the electronically controlled expansion valves 7a, 7b on both sides of the large indoor heat exchanger A, and connect the indoor unit to the outdoor unit. There is no difference in configuring the . However, on both sides of the reference indoor heat exchanger B, on-off valves 13a and 13b, which are packed valves having an on-off function, must be used.

Further, the parallel circuit 4A is provided with a bypass circuit 14 on the pressure reducing device side and a bypass circuit 15 on the flow rate regulating valve side. Bypass circuit 14 on the pressure reducing device side
is between the electronically controlled expansion valve 7a on the line side of the large indoor heat exchanger A and the packed valve 9, and between the electronically controlled expansion valve 8a and the on-off valve 13a on the line side of the reference indoor heat exchanger B. communicate between. A bypass on-off valve 16 is provided in the middle of this bypass circuit 14 .

On the other hand, the bypass circuit 1 on the flow rate regulating valve side
5 is between the electronically controlled expansion valve 7b on the line side of the large indoor heat exchanger A and the packed valve 9, and between the electronically controlled expansion valve 8b and the on-off valve 13b on the line side of the reference indoor heat exchanger B. communicate between. A bypass on-off valve 17 is provided in the middle of this bypass circuit 15 .

Therefore, in both cooling and heating operations, if the heat load required in each air-conditioned room is within the maximum heat exchange capacity of the reference indoor heat exchanger B, each bypass circuit 14,
The bypass on-off valves 16 and 17 of No. 15 are closed, and the on-off valves 13a and 13b on both sides of the reference indoor heat exchanger B are opened to perform refrigeration cycle operation.

During cooling operation, the refrigerant is guided in the direction of the solid arrow in the figure, and is evaporated in each of the indoor heat exchangers A and B, thereby performing a cooling action in each air-conditioned room. Furthermore, during heating operation, the refrigerant is guided in the direction of the dashed arrow in the figure, and the refrigerant is condensed in each of the indoor heat exchangers A and B, thereby producing a heating effect in each air-conditioned room. Naturally, each electronically controlled expansion valve 7a... functions normally and there is no pressure loss. From this, high reliability of the refrigeration cycle can be maintained.

[0030] In particular, in an air-conditioned room equipped with the large indoor heat exchanger A whose maximum heat exchange capacity is one rank higher, when there is a request for a heat load almost close to the maximum heat exchange capacity, the following should be carried out. Control as described.

That is, during each operation of heating and cooling, the bypass on-off valves 16 and 17 of the bypass circuit 14 on the pressure reducing device side and the bypass circuit 15 on the flow rate adjustment valve side are opened, and the standard indoor heat exchanger with a small maximum heat exchange capacity is opened. The on-off valves 13a and 13b on the line side of vessel B are closed.

[0032] During each operation of cooling and heating, parallel circuit 4A
The refrigerant guided through the electronically controlled expansion valves 7a is controlled to be opened to the maximum extent. Then, the refrigerant guided to the line side of the large indoor heat exchanger A is transferred to the electronically controlled expansion valve 7.
A or 7b is directly introduced into A into the large indoor heat exchanger.

When the refrigerant guided through the line side of the reference indoor heat exchanger B is led out from the electronically controlled expansion valve 8a or 8b, the on-off valve 13a or 13b is closed, and the bypass on-off valve 16 or 17 is closed. From the open position, it is led to the bypass circuit 14 or 15, as shown by the dashed-dotted line arrow in the figure. And furthermore,
It joins with the refrigerant guided through the line side of the large indoor heat exchanger A, and is led to the large indoor heat exchanger A, where it performs a heat exchange action.

In the end, all the refrigerant flowing through the refrigeration cycle is led to the large indoor heat exchanger A, which has a large maximum heat exchange capacity, so that a sufficient amount of refrigerant is secured and a high capacity is maintained. As before, an amount of refrigerant within the allowable range flows through the electronically controlled expansion valves 7a, so there is no pressure loss.

In this way, by adding the on-off valves 13a, 13b and the bypass circuits 14, 15, a large indoor heat exchanger with a maximum heat exchange capacity one rank higher can be used only in air-conditioned rooms where a large heat load is required. In the air-conditioned room where A is installed and the standard heat load is required, the standard indoor heat exchanger B having the standard maximum heat exchange capacity is installed as is, and refrigeration cycle operation can be performed.

In the above embodiment, the bypass circuits 14 and 15 were provided so as to communicate with each other the pipes of the parallel circuit 4A, but the present invention is not limited to this. For example, the electronically controlled expansion valve 7 on the line side of the large indoor heat exchanger A
A bypass circuit is provided in parallel with a and 7b. This bypass circuit is still provided with an on-off valve.

Therefore, when there is a request for a heat load close to the maximum heat exchange capacity of the large indoor heat exchanger A, the refrigerant is guided to both the bypass circuit and the electronically controlled expansion valves 7a and 7b parallel thereto. Similar to the above embodiment, there is no pressure loss in the electronically controlled expansion valves 7a, 7b. With such a piping configuration, the refrigerant is also guided to the reference indoor heat exchanger B, so there is no need to interrupt the heat exchange action in the air-conditioned room. In addition, various modifications can be made within the scope of the invention.

[0038]

[Effects of the Invention] As explained above, the present invention has the advantage that when an extremely large heat load is required in an air-conditioned room equipped with an indoor heat exchanger with a large heat exchange capacity, the refrigerant of the standard indoor heat exchanger can be The inlet side on-off valve is closed and the bypass on-off valve is opened to direct all refrigerant to the indoor heat exchanger with a large heat exchange capacity, so it is compatible with the indoor heat exchanger with the standard maximum heat exchange capacity. Even with electronically controlled expansion valves, problems such as pressure loss do not occur, and any one of the multiple indoor heat exchangers can be operated in a refrigeration cycle equipped with a larger indoor heat exchanger with a maximum heat exchange capacity of one rank higher. This has the effect of improving the reliability of the refrigeration cycle and reducing the burden on the user.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a refrigeration cycle of an air conditioner, showing one embodiment of the present invention.

FIG. 2 is a configuration diagram of a refrigeration cycle of an air conditioner according to a conventional example of the present invention.

FIG. 3 is a partially modified view thereof.

[Explanation of symbols]

A... Large indoor heat exchanger, B... Standard indoor heat exchanger, 7a, 7
b, 8a, 8b...electronically controlled expansion valve, 13a, 13b...on/off valve, 14,15...bypass circuit, 16,17...bypass on/off valve.

Claims (1)

[Claims] Claim 1: An air conditioner in which a plurality of indoor heat exchangers are connected in parallel to a refrigeration cycle circuit, and an electronically controlled expansion valve is provided on the refrigerant introduction side of each indoor heat exchanger. The exchanger allows for the combination of an indoor heat exchanger with the standard maximum heat exchange capacity and an indoor heat exchanger with a larger maximum heat exchange capacity, so the indoor heat exchanger refrigerant with the standard maximum heat exchange capacity is Install an on-off valve on the introduction side,
A bypass circuit communicates between this on-off valve and the electronically controlled expansion valve, and between the indoor heat exchanger with a large maximum heat exchange capacity and the electronically controlled expansion valve, and a bypass on-off valve is provided in this bypass circuit. An air conditioner characterized by: